program exemplo2pg83(input,output);
var n,s,i:integer;
  procedure soma;
     var q:integer;
     begin
       q:=i*i;
       if (i div 2)*2=i
       then s:=s+q
       else s:=s-q
     end;
begin
   read(n);
   s:=0;
   i:=0;
   while i<=n
   do begin
         soma;
         write(s);
         i:=i+1
      end
end.

